cbc: add switch --config-transport to choose HTTP/CCCP

Change-Id: I4ddc2ac37d23ca84fddba0f28e8047879dfeb548
Reviewed-on: http://review.couchbase.org/33042
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>